1. Field of Endeavor
The present invention relates to particles and more particularly to a safe fluorescent particle.
2. State of Technology
The article “An examination of the urban dispersion curves derived from the St. Louis dispersion study” by Akula Venkatram in Atmospheric Environment 39 (2005) 3813-3822, describes an aerosol study that was conducted over the period 1963-1965. The aerosol study was an investigation of large scale air dispersal to track particulate migration over vast areas, or for urban particle dispersion studies. Researchers performing these studies rely on air dispersion models and gas tracer tests to determine the movement and flow of aerosols in urban environments such as in cities—around and through occupied buildings—because “safe” particles were not available at the time. The St. Louis study consisted of a series of 26 daytime and 16 evening experiments in which fluorescent zinc cadmium sulfide particles were released near ground level at two different locations under a variety of meteorological conditions. During the first year of the experiments, the release was at ground level in a relatively open area in a park located west of the downtown area. In the second year, the tracer was released from the top of a three-story building surrounded by trees and similar buildings. The main downtown area, consisting of buildings with an average height of 40 m, was about 5 km away from both release locations.
In an article titled, “U.S. Is Deploying a Monitor System for Germ Attacks,” by Judith Miller in The New York Times on Jan. 22, 2003, it was reported, “To help protect against the threat of bioterrorism, the Bush administration on Wednesday will start deploying a national system of environmental monitors that is intended to tell within 24 hours whether anthrax, smallpox and other deadly germs have been released into the air, senior administration officials said today. The system uses advanced data analysis that officials said had been quietly adapted since the September 11 attacks and tested over the past nine months. It will adapt many of the Environmental Protection Agency's 3,000 air quality monitoring stations throughout the country to register unusual quantities of a wide range of pathogens that cause diseases that incapacitate and kill . . . The new environmental surveillance system uses monitoring technology and methods developed in part by the Department of Energy's national laboratories. Samples of DNA are analyzed using polymerase chain reaction techniques, which examine the genetic signatures of the organisms in a sample, and make rapid and accurate evaluations of that organism . . . . Officials who helped develop the system said that tests performed at Dugway Proving Ground in Utah and national laboratories showed that the system would almost certainly detect the deliberate release of several of the most dangerous pathogens. ‘Obviously, the larger the release, the greater the probability that the agent will be detected,’ an official said. ‘But given the coverage provided by the E.P.A. system, even a small release, depending on which way the wind was blowing and other meteorological conditions, is likely to be picked up.”’
In an article titled, “Biodetectors Evolving, Monitoring U. S. Cities,” by Sally Cole in the May 2003 issue of Homeland Security Solutions, it was reported, “The anthrax letter attacks of 2001, and subsequent deaths of five people, brought home the reality of bioterrorism to Americans and provided a wake-up call for the U.S. government about the need for a method to detect and mitigate the impact of any such future attacks. Long before the anthrax letter attacks, scientists at two of the U.S. Department of Energy's national laboratories, Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), were busy pioneering a “biodetector” akin to a smoke detector to rapidly detect the criminal use of biological agents. This technology is now expected to play a large role in the U.S. government's recently unveiled homeland security counter-terrorism initiative, Bio-Watch, which is designed to detect airborne bioterrorist attacks on major U.S. cities within hours. Announced back in January, Bio-Watch is a multi-faceted, multi-agency program that involves the U.S. Department of Energy, the Environmental Protection Agency (EPA), and the U.S. Department of Health and Human Services' Centers for Disease Control and Prevention (CDC). Many of the EPA's 3,000 air-quality monitoring stations throughout the country are being adapted with biodetectors to register unusual quantities of a wide range of pathogens that cause diseases that incapacitate and kill, according to the EPA. The nationwide network of environmental monitors and biodetectors, which reportedly will eventually monitor more than 120 U.S. cities, is expected to detect and report a biological attack within 24 hours. Citing security reasons, the EPA declined to disclose further details about the program at this time . . . . The Autonomous Pathogen Detection System (APDS) is a file-cabinet-sized machine that sucks in air, runs tests, and reports the results itself. APDS integrates a flow cytometer and real-time PCR detector with sample collection, sample preparation, and fluidics to provide a compact, autonomously operating instrument capable of simultaneously detecting multiple pathogens and/or toxins. The system is designed for fixed locations, says Langlois, where it continuously monitors air samples and automatically reports the presence of specific biological agents. APDS is targeted for domestic applications in which the public is at high risk of exposure to covert releases of bioagents—subway systems, transportation terminals, large office complexes, and convention centers . . . . APDS provides the ability to measure up to 100 different agents and controls in a single sample; Langlois says. ‘It's being used in public buildings right now.’ The latest evolution of the biodetector, APDS-II, uses bead-capture immunoassays and a compact flow cytometer for the simultaneous identification of multiple biological simulants. Laboratory tests have demonstrated the fully autonomous operation of APDS-II for as long as 24 hours.”
U.S. Pat. No. 6,498,041 issued Dec. 24, 2002 to Mary Beth Tabacco and Laura C. Taylor for optical sensors for rapid, sensitive detection provides the following state of technology information: “The threat from biological weapons as tools of modern warfare and urban terrorism is increasing. Development of early detection, counter measures, and remediation technology is a high priority in many military, government and private laboratories around the world. Biological warfare (BW) agents of critical concern are bacterial spores, such as Bacillus anthracis (anthrax), Clostridium tetani (tetanus), and Clostridium botulinum (botulism).”
United States Published Patent Application No. 2004/0125371 by Richard Chang et al published Jul. 1, 2004 for method and instrumentation for measuring fluorescence spectra of individual airborne particles sampled from ambient air provides the following state of technology information: “Detecting chemical composition of particles is desirable for a variety of applications, such as in detecting fugitive aerosol pollutants, differentiating between biological and non-biological aerosols (and classifying biological particles), or investigating aerosol drug-delivery systems. Light scattering particle counters are based on a single-particle detection approach, wherein particles entrained in air are rapidly drawn through an intense light beam, and light scattered by single particles is sensed and used to infer particle size. Recently, this approach has been expanded to measurement of the two-dimensional angular optical scattering of single aerosol particles and the intrinsic laser-induced fluorescence (LIF) of particles, both of which may be used for additional characterization. LIF can be used in addition to (or instead of) elastic scattering. These efforts concentrate on measurement of the undispersed fluorescence of particles, and consequently only have limited potential for providing information on particle composition. More capable techniques to measure the LIF spectra of single aerosol particles have been recently developed in order to obtain better aerosol classification. In these investigations the emphasis was on detecting biological aerosols using both cw and pulsed laser sources with wavelengths ranging from 263 nm to 488 nm.”